This is due to how we store these values internally. While the field is represented as a string, it is actually a integer that we then transform at display time. In your case, you should be able to use a value like 201610 to filter for October 2016 of your MY(Date) field.

You can always figure out things like this by following the steps below.

Heartly thanks Dan!! your suggestion and guide worked perfectly. many thanks, since I played too much to get this work but I failed every time.

Can you help me more? I have to apply same filter to another dashboard also but that filter is coming from blended data-source.

Like this: I have column from blended source : "report period str" and it is calculated field from date column like below. It doing nothing but just populating "year-quarter" or "year-month" in proper format as per parameter selected.